DEVIL SURVIVOR2 the ANIMATION

Akemi Nakajima is a student in the "gifted class" in his high school. After being bullied and beaten by another student who a female student invoked, Nakajima uses his advanced computer skills to create the "Demon Summoning Program." He summons demons to attack the two, but he gets carried away and ultimately kills them. Now sick with the power of the demon realm Makai in his hands, he summons the demon lord Loki. Realizing summoning such a powerful demon was a mistake, Nakajima sets out to reverse the problem he has created by any means.

It tells Yamato's past prior to the Purge of Polaris.

The setting of Devil Survivor 2 spans the whole country of Japan. It tells the story of Japanese high-school students who receive emails from a website foretelling their friend's deaths. Mysterious creatures invade the country, and the students enter a pact, enabling them to summon demons from their cell phones with a special Devil Summoning App.

After demons break through into the human world, Tokyo must be quarantined. Without power and stuck in a supernatural warzone, 17-year-old Kazuya has only one hope: he must use the COMP, a device created by his cousin Naoya capable of summoning and subduing demons, to defeat the invaders and take back the city. (Source: Kodansha USA)